Method for measuring the rheological properties of fluids in the bore holes of deep-wells

ABSTRACT

A measuring method in which measurements of the rheological properties of fluids in bore holes of deep-wells may be carried out under such conditions, which conform to the actual operative condition in the bore hole. The conditions simulate the flow relationship in the annular space at the location of the most intense demand on the flushing fluid is patterned or modeled in a known manner. Pursuant to a further characteristic of the invention, in the patterning there are generated laminar flow conditions.

United States Patent [191 Megyeri et al.

METHOD FOR MEASURING THE RHEOLOGICAL PROPERTIES OF FLUIDS IN THE BORE HOLES OF DEEP-WELLS Inventors: Mihaly Megyeri, 25, Oswald utca;

Jeno Molnar, 10, Tolbuchin setany, both of Nagykanisza, Hungary Filed: Nov. 30, 1973 Appl. No.: 420,522

US. Cl. 73/153 Int. Cl E21b 47/06 Field of Search 73/153, 154, 152

References Cited UNITED STATES PATENTS 2/1961 Armistead et al. 73/l53 X 51 May 27, 1975 3,209,323 9/1965 Grossman, Jr. 73/152 UX 3,455,158 7/1969 Richter, Jr et a] 73/154 Primary Examiner-Jerry W. Myracle l 5 7] ABSTRACT 3 Claims, 1 Drawing Figure 1 METHOD FOR MEASURING THE RHEOLOGICAL PROPERTIES OF FLUIDS IN THE BORE HOLES OF DEEP-WELLS FIELD OF THE INVENTION DISCUSSION OF THE PRIOR ART As is known in the art, the rheological properties of flushing or scavenging fluids are determined by means of laboratory measuring apparatus and under testing conditions which deviate from the actual condition of the bore hole and the therein reigning flow-, temperatureand pressure relationships. Publications which are pertinent thereto are: Rogers: Composition and Properties of Oil Well Drilling Fluids, l52l88 (1963); Combs, Whitemire: The Oil and Gas Journal, 30, 108-113 (1968); Gilicz: 'Banyaszati Lapok, 10, 298-306 (1969).

The disadvantage of the known methods lies in that the rheological parameters which are determined with laboratory equipment under laboratory conditions, upon their conversion to effective or actual operative conditions, are on the one hand subject to the occurrence of numerous errors and, on the other hand, with these errors not being controllable.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to formulate a measuring method in which the measurements may be carried out under such conditions, which conform to the actual operative conditions in the bore hole.

According to the present invention, this object is inventively solved wherein the flow relationship in the annular space at the location of the most intense de mand on the flushing fluid is patterned or modeled in a known manner. Pursuant to a further characteristic of the invention, in the patterning there are generated laminar flow conditions.

BRIEF DESCRIPTION OF THE DRAWING The invention is now more fully described in the following detailed description of a preferred embodiment, reference being bad to the single FIGURE of the accompanying drawing.

DETAILED DESCRIPTION Referring to the drawing, there is illustrated proxi mate the foot or bottom of a bore hole, a measuring arrangement which is supported at the lower end of the bore rod. The measurements are preferably taken at the bottom of the bore hole or proximate thereto, since with respect to the fluid which is to be tested, this region is the location of the greatest demands thereon.

The fluid which is to be tested, for example the flushing or scavenging fluid for the deep-well, is conveyed downwardly within the hollow bore rod 1 of a bore or drilling installation toward the lower rod end having fastened thereto the measuring arrangement. The diameter of the tube section 2 of the measuring arrangement is selected to be smaller than the inner diameter of the hollow, tubular bore rod 1, and the pressure differential which is generated by the friction losses is continually measured by means of a depth-pressure measuring apparatus 3. The depth-pressure measuring apparatus 3 is connected, at one side, at sensor connections thereof through a conduit 4 with the tube section 2, and at the other side, through a conduit 5 with the housing of a diagramrecorder. Hydraulic connection between the fluid being tested the depth-pressure measuring apparatus 3 is assured through the conduit 4 and the oil which is located within the depthpressure measuring apparatus. Below the tube section 2 there is mounted a pressure-and temperature measuring apparatus 6.

The diameter and length of the tube section 2, as well as the pressure level-parameters of the depth-pressure measuring apparatus are selected on the basis of known hydraulic relationships and practical experiences.

During the measuring sequence there may be carried out, while varying the flow or, effectively, flushing rates of the fluids being tested, the measurements at desired flow conditions which in essence, are patterned on the conditions encountered in the annular bore hole space during actual operation. It is preferable that the arrangement be constructed from at least two tube sections 2 having different diameters, and which are provided with separate measuring instruments. In this instance, the accuracy of measurement is enhanced, while on the other hand the measuring range is increased, and for each flow rate of the fluid being tested there are obtained two data grouping relating to two thrust velocity regions.

The flushing fluid of the bore hole is a work slush having a specific weight of 1.8 p/cm but which has a viscosity of 600 cP as measured in the laboratory. At the end of the bore rod having a diameter of 1 13 mm, there is located a measuring tube of 7.5mm in diameter and 1.14 meters in length. The measurement is carried out at a depth of 3,000 meters and with a flushing flow rate of 19 dm /min. There may be expected a measurable pressure differential of 10.0 atmospheres. From the measured pressure differential, on the basis of known relationships in the flow technology, the values of the plastic viscosity may then be calculated.

The parameters of the measuring tube are considered on the basis of calibration with waterprior to and subsequent to the measuring.

The advantageous properties of the method according to the invention may be summarized, as follows:

1. The rheological properties of the flushing or scavenging fluid may be determined truthfully accurate, and in conformance with actual operating conditions; 1

2. The measuring can be accomplished in a simple manner;

3. The measurements may be precisely effected at desired flow conditions over an extremely broad range; and

4. In the practical application of the method pursuant to the invention, the installation therefore may be simply assembled of known structural components.

While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made which come within the scope of the disclosure of the specification.

What is claimed is:

1. In a method of measuring the rheological properties of fluids forming drilling mud in the bore holes of said bore rod, and patterning the shearing velocity of the drilling'mud to the most stringent predetermined operating demands thereon. v

2. A method as claimed in claim 1, comprising imposing a laminar fluid flow condition for effecting said measuring sequence.

3. A method as claimed in claim 1, said measuring comprising measuring the pressure differential acting on said fluid proximate the lower end of said bore hole. 

1. In a method of measuring the rheological properties of fluids forming drilling mud in the bore holes of deep-wells, comprising conveying the fluid downwardly into the bore hole interiorly of a hollow bore rod, measuring the viscosity of the drilling mud while being pressed through the bore rod and the bore hole as a function of its shearing velocity, and evacuating the fluid upwardly in the annular space encompassing said bore rod, the improvement comprising; continuously measuring the rheological properties of said fluid on the basis of conditions responsive to the velocity of the fluid in motion while drilling in the annular space about said bore rod, and patterning the shearing velocity oF the drilling mud to the most stringent predetermined operating demands thereon.
 2. A method as claimed in claim 1, comprising imposing a laminar fluid flow condition for effecting said measuring sequence.
 3. A method as claimed in claim 1, said measuring comprising measuring the pressure differential acting on said fluid proximate the lower end of said bore hole. 